"Look, she's so fat!"

When I was in 7th grade, nobody knew me yet in my new classes. There was this guy who was known for being a douche, yet I still had a crush on him.

One day he and a friend were walking behind me, and I heard him say, "Look, she's so fat!"

A few months later, we were practically best friends in class. He called another girl fat, but I thought he was talking about me. When I asked, he said, "No! Why would I call you fat?" To which I responded, "You actually have before. Ages ago. You said it while you were walking behind me." 

He then spent the next seven minutes completely denying that he ever said this, that he didn't even know who I was at the time.  

That was the first time I that realized how easy it is for people to make comments that may be insignificant to them but everything to you. So insignificant that they don't even remember making them. So insignificant to him, but so scarring and formative for me.